1. Field of the Invention
The invention relates to an electronic musical instrument constituted by placing parts such as a keyboard portion, a sound source portion, and so on in a main body portion and, more specifically, to an electronic musical instrument in which a part selected from among parts of a plurality of grades can be placed and which can be changed in grade by replacement of the part.
2. Description of the Related Art
Generally, to meet wide-ranging needs of consumers, it is often to provide electronic musical instruments such as an electronic organ and so on by a plurality of kinds of models of different grades from a high-grade model that is highly functional at a high price to a low-grade model that is less functional at a low price. There is a known electronic organ as the above-described one, for example, by the name of “Electone (trade mark)” manufactured and sold by the assignee of this application. For development of such an electronic musical instrument, it takes much cost to independently develop and manufacture each model, and therefore a method is employed in which portions that can be made common among the models are made common and different parts are placed in a common portion in accordance with the function. The employment of such a method enables an electronic musical instrument to be upgraded without replacement of the common portion only by replacing parts of the low-grade model with parts corresponding to the high-grade model.
However, when such an upgrade is performed, there is a problem of updating the control program. As for this point, since the same CPU or the like, which constitutes the controller, is often usable as hardware itself even in different grades, the CPU is often provided in the common potion. Then, in an electronic musical instrument manufactured as the low-grade model, the control portion performs control using, as a matter of course, a control program for controlling the common portion and the parts of the low-grade model. In this event, even through only the parts are replaced with those of the high-grade model, the controller cannot control the new parts if the control program for use in control is unchanged. Therefore, it is also necessary to conduct work of rewriting the control program or replacing a program ROM storing the control program at the time of upgrade.
As means for solving such a problem, a configuration is described in paragraphs 0024 to 0026 of JP, H11-73185, A, in which a ROM stores in advance a control program for making an electronic musical instrument function as a high-grade model and a control program for making it function as a low-grade model, and an external DIP switch sets which model function the electronic musical instrument performs.
According to this configuration, when the electronic musical instrument is upgraded by replacement of parts, the setting of the DIP switch is changed in accordance with the upgrade to thereby change the control program so that the controller can control the parts after the replacement.
However, in the configuration described in the above publication, it is necessary to change the setting of the switch at the time of upgrade, which leads to a problem that the electronic musical instrument does not normally operate when the change operation is forgotten.
In addition, there is a constraint on design that the DIP switch should be placed at an operable position, and the DIP switch located at a position where the operation is not easy increases the labor of upgrade work. On the other hand, there is another problem that when the switch is located at a position where it is too conspicuous and therefore a user operates it by mistake, the control program is unintentionally changed, whereby the electronic musical instrument does not normally operate.
Further, there is another problem that a change of the DIP switch changes which model function the whole electronic musical instrument performs, and this configuration cannot cope with the case of individual upgrade of the parts.